To develop a nonradioactive breath test using the stable isotope 13C Spirulina for measuring gastric emptying of solids. To assess the correlation between t 1/2 obtained from 13C Spirulina breath test and t 1/2 of the simultaneously performed scintigraphic technique in health subjects. This study will most likely validate a new method to noninvasively measure gastric emptying using stable isotopes. It has immense potential for studies of nausea, vomiting and abdominal symptoms in pediatric and obstetric practice and in community or epidemiologic studies. We performed simultaneous 13C-spirulina breath test and scintigraphy in 30 healthy volunteers from November 11, 1997, to March 13, 1998. From these data, we developed a new accurate model for solid gastric empthing using multiple linear regression analysis and wrote an abstract which we will present at the Biennial Meeting of the American Motility Society this month in Philadelphia.